diff options
author | Johan Hovold <johan@kernel.org> | 2015-05-18 17:34:11 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-05-24 18:30:03 +0200 |
commit | 6cb4f4df686e6515f43d9fec3f43226d408999b3 (patch) | |
tree | edf90f778d18418b2313573494b66391ffe2b5c2 /drivers/usb/class | |
parent | USB: devio: fix a condition in async_completed() (diff) | |
download | linux-6cb4f4df686e6515f43d9fec3f43226d408999b3.tar.xz linux-6cb4f4df686e6515f43d9fec3f43226d408999b3.zip |
USB: cdc-acm: use idr to manage minor numbers
Use the idr-interface rather than a static table to manage minor-number
allocations.
This allows us to easily switch over to fully dynamic minor allocations
when the TTY-layer can handle that.
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class')
-rw-r--r-- | drivers/usb/class/cdc-acm.c | 38 |
1 files changed, 17 insertions, 21 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 5c8f58114677..877b637e7f7b 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -46,6 +46,7 @@ #include <linux/usb/cdc.h> #include <asm/byteorder.h> #include <asm/unaligned.h> +#include <linux/idr.h> #include <linux/list.h> #include "cdc-acm.h" @@ -56,27 +57,27 @@ static struct usb_driver acm_driver; static struct tty_driver *acm_tty_driver; -static struct acm *acm_table[ACM_TTY_MINORS]; -static DEFINE_MUTEX(acm_table_lock); +static DEFINE_IDR(acm_minors); +static DEFINE_MUTEX(acm_minors_lock); static void acm_tty_set_termios(struct tty_struct *tty, struct ktermios *termios_old); /* - * acm_table accessors + * acm_minors accessors */ /* - * Look up an ACM structure by index. If found and not disconnected, increment + * Look up an ACM structure by minor. If found and not disconnected, increment * its refcount and return it with its mutex held. */ -static struct acm *acm_get_by_index(unsigned index) +static struct acm *acm_get_by_minor(unsigned int minor) { struct acm *acm; - mutex_lock(&acm_table_lock); - acm = acm_table[index]; + mutex_lock(&acm_minors_lock); + acm = idr_find(&acm_minors, minor); if (acm) { mutex_lock(&acm->mutex); if (acm->disconnected) { @@ -87,7 +88,7 @@ static struct acm *acm_get_by_index(unsigned index) mutex_unlock(&acm->mutex); } } - mutex_unlock(&acm_table_lock); + mutex_unlock(&acm_minors_lock); return acm; } @@ -98,14 +99,9 @@ static int acm_alloc_minor(struct acm *acm) { int minor; - mutex_lock(&acm_table_lock); - for (minor = 0; minor < ACM_TTY_MINORS; minor++) { - if (!acm_table[minor]) { - acm_table[minor] = acm; - break; - } - } - mutex_unlock(&acm_table_lock); + mutex_lock(&acm_minors_lock); + minor = idr_alloc(&acm_minors, acm, 0, ACM_TTY_MINORS, GFP_KERNEL); + mutex_unlock(&acm_minors_lock); return minor; } @@ -113,9 +109,9 @@ static int acm_alloc_minor(struct acm *acm) /* Release the minor number associated with 'acm'. */ static void acm_release_minor(struct acm *acm) { - mutex_lock(&acm_table_lock); - acm_table[acm->minor] = NULL; - mutex_unlock(&acm_table_lock); + mutex_lock(&acm_minors_lock); + idr_remove(&acm_minors, acm->minor); + mutex_unlock(&acm_minors_lock); } /* @@ -497,7 +493,7 @@ static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty) dev_dbg(tty->dev, "%s\n", __func__); - acm = acm_get_by_index(tty->index); + acm = acm_get_by_minor(tty->index); if (!acm) return -ENODEV; @@ -1316,7 +1312,7 @@ made_compressed_probe: goto alloc_fail; minor = acm_alloc_minor(acm); - if (minor == ACM_TTY_MINORS) { + if (minor < 0) { dev_err(&intf->dev, "no more free acm devices\n"); kfree(acm); return -ENODEV; |